Nanostructured metal oxide/conjugated polymer hybrid solar cells by low temperature solution processes

Abstract

In this article, we have proposed a nanostructured photovoltaic device based on the ZnO nanostructures/poly(3-hexylthiophene)(P3HT):TiO₂ nanorod hybrid by solution processes at low temperature. An array of ZnO nanorods with a larger size of ∼50 nm in diameter and ∼180 nm in length are grown to provide direct pathways for efficient charge collection. TiO₂ nanorods with a size of ∼5 nm in diameter and ∼20–30 nm in length are incorporated into polymers to facilitate charge separation and transport by providing an increased interfacial area and a more effective transport pathway. The device performance with the inclusion of TiO₂ nanorods exhibits a seven times increase in the short circuit current with respect to that without TiO₂ nanorods. The device performance can be further enhanced after completely removing the residual surfactant on the TiO₂ nanorods using the ligand exchange method, giving a short circuit current density of 2.67 mA cm⁻² and a power conversion efficiency of 0.59% under Air Mass 1.5 (100 mW cm⁻²) illumination.